The present application pertains to the design and manufacture of circuit boards, and more specifically the connection of devices such as memory modules to circuit boards.
Conventionally, as shown in FIGS. 1A and 1B, a memory device 100 may have a number of pins 102 for transferring information from the memory device 100 to a circuit board 104. The memory device 100 connects to the circuit board 104 via a slot 106 that extends from the circuit board 104 and is fixed to the circuit board 104.
The conventional slot 106 is external to the circuit board 104. That is, on the circuit board 104, the slot 106 is provided in a protrusion that attaches to the circuit board 104 and rises from the surface of the circuit board 104. The memory device 100 sits inside the slot 106 and is supported on its sides by the external protrusion.
The conventional memory device 100 is positioned in the slot 106 by pushing the memory module 100 into the slot 106 so that the pins 102 make contact with corresponding interconnects in the slot 106. Once the memory device 100 is seated in the slot 106, the memory device 100 is held in place by friction and may be further secured by actuating one or more clips 108, which lock the memory device 100 into position in the slot 106.
This conventional approach suffers from a number of drawbacks. For example, due to the above-described method of securing the memory device 100 in the slot 106, problems such as fretting are common. Fretting refers to the wear between two surfaces that are in contact with each other under a load. When the two surfaces grind against each other, one or both of the surfaces can wear away. In the case of a memory device 100 connected to a circuit board 104 via pins 102 and interconnects, fretting may cause the pins 102 and interconnects to wear away. Thus, some information that is intended to be transferred between the memory device 100 and the circuit board 104 may be unable to be transferred due to the absence of a suitable pathway for the information.
Due to the presence of fretting, among other problems, the connection of the memory device 100 to the board 104 is not rugged. Both the memory device 100 and the board 104 are therefore subject to wear and premature failure.
Fretting is particularly prevalent in the presence of vibration, which is a normal occurrence even on stationary circuit boards. Fretting may become a bigger problem in the presence of a high-vibration environment, such as a circuit board mounted in the head of a missile or on a moving vehicle.
Furthermore, the conventional slot 106 takes up space on the circuit board 104 beyond the dimensions of the memory device 100. Therefore, the circuit board 104 is larger in length and width (i.e., the x-axis and the y-axis of the board) than might otherwise be necessary in order to accommodate the length and width of the memory device 100. Moreover, because the slot 106 extends upward from the circuit board 104 (i.e., along the z-axis of the board), the circuit board 104, when deployed in conjunction with one or more memory devices 100, is taller than might otherwise be necessary in order to accommodate the height of the memory device 100. This limits the number of circuit boards 104 that can be stacked in a given space, which in turn limits the computing power of a system employing such circuit boards 104.